在nsmutablearray中移动对象

Question

我有一个NSMutableArray;

NSMutableArray
--NSMutableArray
----NSDictionary
----NSDictionary
----NSDictionary
--NSMutableArray
----NSDictionary
----NSDictionary
----NSDictionary

我想将第一个NSDictionary移动到第二个NSMutableArray.这是代码:

id tempObject = [[tableData objectAtIndex:fromSection] objectAtIndex:indexOriginal];
[[tableData objectAtIndex:fromSection] removeObjectAtIndex:indexOriginal];
[[tableData objectAtIndex:toSection] insertObject:tempObject atIndex:indexNew];

它删除了对象,但无法将对象插入新位置.错误是:

[CFDictionary retain]: message sent to deallocated instance 0x4c45110

在头文件中:

NSMutableArray *tableData;
@property (nonatomic, retain) NSMutableArray *tableData;

我如何重新排序/移动nsmutablearray中的对象？

Answer 1

从可变数组中删除对象时,它会发送一条release消息.因此,如果没有其他内容保存对它的引用,则该对象将被释放.

所以你可以简单地重新排序语句:

[[tableData objectAtIndex:toSection] insertObject:tempObject atIndex:indexNew];
[[tableData objectAtIndex:fromSection] removeObjectAtIndex:indexOriginal];

...或明确保持对象存活:

[tempObject retain];
[[tableData objectAtIndex:fromSection] removeObjectAtIndex:indexOriginal];
[[tableData objectAtIndex:toSection] insertObject:tempObject atIndex:indexNew];
[tempObject release];

阅读Array Fundamentals和Mutable Arrays以获取更多详细信息.